The influence of edges as salient features in haptic shape perception of 3D objects

Salient features help identify objects. However, they can also influence subsequent comparison between objects. In this study, we investigate the influence of edges on perception of the shape of 3D objects. We tested two conditions in which subjects were asked to indicate the orientation of a block by exploring it either statically without touching the edges or freely. When edges were excluded, the threshold to determine the orientation of a block was an aspect ratio of 1.030. When the edges were explored, the threshold was 1.045. We conclude that edges disrupt the precision at which 3D objects can be perceived.